This invention relates to a novel cyclohexane derivative and a liquid crystal composition containing the same.
Display elements having liquid crystals applied therein utilize the optical anisotropy and dielectric anisotropy of liquid crystals, and they have various modes such as T-N (twisted nematic) type, DS (dynamic scattering) type, guest-host type, DAP type, etc., depending on their display modes. The properties required for liquid crystal substances used depending on these modes are varied respectively, but requirements common thereto consist in that the substances exhibit liquid crystal phases within as broad a temperature range as possible and also are stable to moisture, heat, liquid, air, etc. At present, however, there is no single compound which satisfies all of such requirements, and it is the present status that liquid crystal compositions obtained by blending several kinds of liquid crystal compounds or compounds similar to liquid crystals have been used.
Japanese patent application laid-open Nos. 55-118427/1980 and 59-170042/1984 disclose the following compounds: ##STR2## wherein R' represents an alkyl group of 1 to 12 carbon atoms and R' represents an alkyl group of 1 to 9 carbon atoms.
Any of these compounds exhibit no liquid crystal phase, but they are compounds similar to liquid crystals which can be used as a liquid crystal composition when blended with other liquid crystal compounds. However, the compounds of the formula (I) have a relatively low viscosity, but have a small dielectric anisotropy value .DELTA..epsilon., while the compounds of the formula (II) have a relatively large dielectric anisotropy value .DELTA..epsilon., but have a high viscosity. Thus either of these compounds have drawbacks.